/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.pdfbox.pdmodel.common;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSStream;

import org.apache.pdfbox.filter.Filter;
import org.apache.pdfbox.filter.FilterManager;

import org.apache.pdfbox.pdmodel.PDDocument;

import org.apache.pdfbox.pdmodel.common.filespecification.PDFileSpecification;

/**
 * A PDStream represents a stream in a PDF document.  Streams are tied to a single
 * PDF document.
 *
 * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
 * @version $Revision: 1.17 $
 */
public class PDStream implements COSObjectable
{
    private COSStream stream;

    /**
     * This will create a new PDStream object.
     */
    protected PDStream()
    {
        //should only be called by PDMemoryStream
    }

    /**
     * This will create a new PDStream object.
     *
     * @param document The document that the stream will be part of.
     */
    public PDStream( PDDocument document )
    {
        stream = new COSStream( document.getDocument().getScratchFile() );
    }

    /**
     * Constructor.
     *
     * @param str The stream parameter.
     */
    public PDStream( COSStream str )
    {
        stream = str;
    }

    /**
     * Constructor.  Reads all data from the input stream and embeds it into the
     * document, this will close the InputStream.
     *
     * @param doc The document that will hold the stream.
     * @param str The stream parameter.
     * @throws IOException If there is an error creating the stream in the document.
     */
    public PDStream( PDDocument doc, InputStream str ) throws IOException
    {
        this( doc, str, false );
    }

    /**
     * Constructor.  Reads all data from the input stream and embeds it into the
     * document, this will close the InputStream.
     *
     * @param doc The document that will hold the stream.
     * @param str The stream parameter.
     * @param filtered True if the stream already has a filter applied.
     * @throws IOException If there is an error creating the stream in the document.
     */
    public PDStream( PDDocument doc, InputStream str, boolean filtered ) throws IOException
    {
        OutputStream output = null;
        try
        {
            stream = new COSStream( doc.getDocument().getScratchFile() );
            if( filtered )
            {
                output = stream.createFilteredStream();
            }
            else
            {
                output = stream.createUnfilteredStream();
            }
            byte[] buffer = new byte[ 1024 ];
            int amountRead = -1;
            while( (amountRead = str.read(buffer)) != -1 )
            {
                output.write( buffer, 0, amountRead );
            }
        }
        finally
        {
            if( output != null )
            {
                output.close();
            }
            if( str != null )
            {
                str.close();
            }
        }
    }

    /**
     * If there are not compression filters on the current stream then this
     * will add a compression filter, flate compression for example.
     */
    public void addCompression()
    {
        List filters = getFilters();
        if( filters == null )
        {
            filters = new ArrayList();
            filters.add( COSName.FLATE_DECODE );
            setFilters( filters );
        }
    }

    /**
     * Create a pd stream from either a regular COSStream on a COSArray of cos streams.
     * @param base Either a COSStream or COSArray.
     * @return A PDStream or null if base is null.
     * @throws IOException If there is an error creating the PDStream.
     */
    public static PDStream createFromCOS( COSBase base ) throws IOException
    {
        PDStream retval = null;
        if( base instanceof COSStream )
        {
            retval = new PDStream( (COSStream)base );
        }
        else if( base instanceof COSArray )
        {
            retval = new PDStream( new COSStreamArray( (COSArray)base ) );
        }
        else
        {
            if( base != null )
            {
                throw new IOException( "Contents are unknown type:" + base.getClass().getName() );
            }
        }
        return retval;
    }


    /**
     * Convert this standard java object to a COS object.
     *
     * @return The cos object that matches this Java object.
     */
    public COSBase getCOSObject()
    {
        return stream;
    }

    /**
     * This will get a stream that can be written to.
     *
     * @return An output stream to write data to.
     *
     * @throws IOException If an IO error occurs during writing.
     */
    public OutputStream createOutputStream() throws IOException
    {
        return stream.createUnfilteredStream();
    }

    /**
     * This will get a stream that can be read from.
     *
     * @return An input stream that can be read from.
     *
     * @throws IOException If an IO error occurs during reading.
     */
    public InputStream createInputStream() throws IOException
    {
        return stream.getUnfilteredStream();
    }

    /**
     * This will get a stream with some filters applied but not others.  This is useful
     * when doing images, ie filters = [flate,dct], we want to remove flate but leave dct
     *
     * @param stopFilters A list of filters to stop decoding at.
     * @return A stream with decoded data.
     * @throws IOException If there is an error processing the stream.
     */
    public InputStream getPartiallyFilteredStream( List stopFilters ) throws IOException
    {
        FilterManager manager = stream.getFilterManager();
        InputStream is = stream.getFilteredStream();
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        List filters = getFilters();
        String nextFilter = null;
        boolean done = false;
        for( int i=0; i<filters.size() && !done; i++ )
        {
            os.reset();
            nextFilter = (String)filters.get( i );
            if( stopFilters.contains( nextFilter ) )
            {
                done = true;
            }
            else
            {
                Filter filter = manager.getFilter( COSName.getPDFName(nextFilter) );
                filter.decode( is, os, stream, i );
                is = new ByteArrayInputStream( os.toByteArray() );
            }
        }
        return is;
    }

    /**
     * Get the cos stream associated with this object.
     *
     * @return The cos object that matches this Java object.
     */
    public COSStream getStream()
    {
        return stream;
    }

    /**
     * This will get the length of the filtered/compressed stream.  This is readonly in the
     * PD Model and will be managed by this class.
     *
     * @return The length of the filtered stream.
     */
    public int getLength()
    {
        return stream.getInt( "Length", 0 );
    }

    /**
     * This will get the list of filters that are associated with this stream.  Or
     * null if there are none.
     * @return A list of all encoding filters to apply to this stream.
     */
    public List getFilters()
    {
        List retval = null;
        COSBase filters = stream.getFilters();
        if( filters instanceof COSName )
        {
            COSName name = (COSName)filters;
            retval = new COSArrayList( name.getName(), name, stream, COSName.FILTER );
        }
        else if( filters instanceof COSArray )
        {
            retval = COSArrayList.convertCOSNameCOSArrayToList( (COSArray)filters );
        }
        return retval;
    }

    /**
     * This will set the filters that are part of this stream.
     *
     * @param filters The filters that are part of this stream.
     */
    public void setFilters( List filters )
    {
        COSBase obj = COSArrayList.convertStringListToCOSNameCOSArray( filters );
        stream.setItem( COSName.FILTER, obj );
    }

    /**
     * Get the list of decode parameters.  Each entry in the list will refer to
     * an entry in the filters list.
     *
     * @return The list of decode parameters.
     *
     * @throws IOException if there is an error retrieving the parameters.
     */
    public List getDecodeParms() throws IOException
    {
        List retval = null;

        COSBase dp = stream.getDictionaryObject( COSName.DECODE_PARMS );
        if( dp == null )
        {
            //See PDF Ref 1.5 implementation note 7, the DP is sometimes used instead.
            dp = stream.getDictionaryObject( COSName.DP );
        }
        if( dp instanceof COSDictionary )
        {
            Map map = COSDictionaryMap.convertBasicTypesToMap( (COSDictionary)dp );
            retval = new COSArrayList(map, dp, stream, COSName.DECODE_PARMS );
        }
        else if( dp instanceof COSArray )
        {
            COSArray array = (COSArray)dp;
            List actuals = new ArrayList();
            for( int i=0; i<array.size(); i++ )
            {
                actuals.add(
                    COSDictionaryMap.convertBasicTypesToMap(
                        (COSDictionary)array.getObject( i ) ) );
            }
            retval = new COSArrayList(actuals, array);
        }

        return retval;
    }

    /**
     * This will set the list of decode parameterss.
     *
     * @param decodeParams The list of decode parameterss.
     */
    public void setDecodeParms( List decodeParams )
    {
        stream.setItem(
            COSName.DECODE_PARMS, COSArrayList.converterToCOSArray( decodeParams ) );
    }

    /**
     * This will get the file specification for this stream.  This is only
     * required for external files.
     *
     * @return The file specification.
     *
     * @throws IOException If there is an error creating the file spec.
     */
    public PDFileSpecification getFile() throws IOException
    {
        COSBase f = stream.getDictionaryObject( COSName.F );
        PDFileSpecification retval = PDFileSpecification.createFS( f );
        return retval;
    }

    /**
     * Set the file specification.
     * @param f The file specification.
     */
    public void setFile( PDFileSpecification f )
    {
        stream.setItem( COSName.F, f );
    }

    /**
     * This will get the list of filters that are associated with this stream.  Or
     * null if there are none.
     * @return A list of all encoding filters to apply to this stream.
     */
    public List getFileFilters()
    {
        List retval = null;
        COSBase filters = stream.getDictionaryObject( COSName.F_FILTER );
        if( filters instanceof COSName )
        {
            COSName name = (COSName)filters;
            retval = new COSArrayList( name.getName(), name, stream, COSName.F_FILTER );
        }
        else if( filters instanceof COSArray )
        {
            retval = COSArrayList.convertCOSNameCOSArrayToList( (COSArray)filters );
        }
        return retval;
    }

    /**
     * This will set the filters that are part of this stream.
     *
     * @param filters The filters that are part of this stream.
     */
    public void setFileFilters( List filters )
    {
        COSBase obj = COSArrayList.convertStringListToCOSNameCOSArray( filters );
        stream.setItem( COSName.F_FILTER, obj );
    }

    /**
     * Get the list of decode parameters.  Each entry in the list will refer to
     * an entry in the filters list.
     *
     * @return The list of decode parameters.
     *
     * @throws IOException if there is an error retrieving the parameters.
     */
    public List getFileDecodeParams() throws IOException
    {
        List retval = null;

        COSBase dp = stream.getDictionaryObject( COSName.F_DECODE_PARMS );
        if( dp instanceof COSDictionary )
        {
            Map map = COSDictionaryMap.convertBasicTypesToMap( (COSDictionary)dp );
            retval = new COSArrayList(map, dp, stream, COSName.F_DECODE_PARMS );
        }
        else if( dp instanceof COSArray )
        {
            COSArray array = (COSArray)dp;
            List actuals = new ArrayList();
            for( int i=0; i<array.size(); i++ )
            {
                actuals.add(
                    COSDictionaryMap.convertBasicTypesToMap(
                        (COSDictionary)array.getObject( i ) ) );
            }
            retval = new COSArrayList(actuals, array);
        }

        return retval;
    }

    /**
     * This will set the list of decode params.
     *
     * @param decodeParams The list of decode params.
     */
    public void setFileDecodeParams( List decodeParams )
    {
        stream.setItem(
            "FDecodeParams", COSArrayList.converterToCOSArray( decodeParams ) );
    }

    /**
     * This will copy the stream into a byte array.
     *
     * @return The byte array of the filteredStream
     * @throws IOException When getFilteredStream did not work
     */
    public byte[] getByteArray() throws IOException
    {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        byte[] buf = new byte[1024];
        InputStream is = null;
        try
        {
            is = createInputStream();
            int amountRead = -1;
            while( (amountRead = is.read( buf )) != -1)
            {
                output.write( buf, 0, amountRead );
            }
        }
        finally
        {
            if( is != null )
            {
                is.close();
            }
        }
        return output.toByteArray();
    }

    /**
     * A convenience method to get this stream as a string.  Uses
     * the default system encoding.
     *
     * @return a String representation of this (input) stream, with the
     * platform default encoding.
     *
     * @throws IOException if there is an error while converting the stream
     *                     to a string.
     */
    public String getInputStreamAsString() throws IOException
    {
        byte[] bStream = getByteArray();
        return new String(bStream);
    }

    /**
     * Get the metadata that is part of the document catalog.  This will
     * return null if there is no meta data for this object.
     *
     * @return The metadata for this object.
     */
    public PDMetadata getMetadata()
    {
        PDMetadata retval = null;
        COSStream mdStream = (COSStream)stream.getDictionaryObject( COSName.METADATA );
        if( mdStream != null )
        {
            retval = new PDMetadata( mdStream );
        }
        return retval;
    }

    /**
     * Set the metadata for this object.  This can be null.
     *
     * @param meta The meta data for this object.
     */
    public void setMetadata( PDMetadata meta )
    {
        stream.setItem( COSName.METADATA, meta );
    }

    /**
     * Get the decoded stream length.
     *
     * @since Apache PDFBox 1.1.0
     * @see <a href="https://issues.apache.org/jira/browse/PDFBOX-636">PDFBOX-636</a>
     * @return the decoded stream length
     */
    public int getDecodedStreamLength()
    {
        return this.stream.getInt(COSName.DL);
    }

    /**
     * Set the decoded stream length.
     *
     * @since Apache PDFBox 1.1.0
     * @see <a href="https://issues.apache.org/jira/browse/PDFBOX-636">PDFBOX-636</a>
     * @param decodedStreamLength the decoded stream length
     */
    public void setDecodedStreamLength(int decodedStreamLength)
    {
        this.stream.setInt(COSName.DL, decodedStreamLength);
    }

}
